- Q.My client's old wood
windows are badly in need of a new paint job. My
client, a sailor, suggested using a high-performance
polyurethane enamel boat paint on the windows to cut
down on future maintenance. It seems to me that if a
finish can adhere to the hull of a wooden boat, it
should be able to perform well on a wooden window, but
I've never used this paint in this application before.
Is it a good idea?
A.Bill Feist, a former
wood-finishes researcher with the Forest Products
Laboratory in Madison, Wis., responds:
Normally, I encourage people to use boat paints and
varnishes for a number of nonmarine uses because of
the general high quality of these finishes. But in
this case, I think doing so might be a mistake.
Even though polyurethane enamels are made for
many different surfaces on boats, polyurethanes in
general are known for their brittleness —
and enamels are even more brittle than flat or
satin paints. This brittleness is okay where there
is not a lot of wood movement. But an older wood
window — especially the sill — is
subject to considerable seasonal shrinking and
swelling, which could result in premature cracking
and peeling.
The best approach for weathered wood windows is
to properly prep the substrate by removing all the
old paint and carefully sanding the wood smooth,
then cleaning with a detergent and bleach solution
followed by a clear-water rinsing. When the wood
has thoroughly dried, treat all of the bare
surfaces with a paintable water-repellent
preservative, such as Wolman's Woodlife Classic
Clear Wood Preservative or Woodlife CopperCoat
Green Wood Preservative (800/556-7737,
www.wolman.com). Be sure to follow the
manufacturer's specific directions for using these
wood treatments.
After treatment, prime with a quality alkyd
primer (I'd even consider using two coats), and
top-coat with two coats of 100 percent acrylic
satin latex house paint.